2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/26732The problem of coherent vortex and zonal jet formation in a system of nonlinear Rossby waves is considered from the point of view of the late time steady state achieved by free decay of a given initial state. Statistical equilibrium equations respecting all conservation laws are constructed, generalizing those derived previously for 2D inviscid Euler flow. Jet-like solutions are ubiquitous, with large coherent vortices existing only when there is uniform background flow with the precise velocity to cancel the beta effect.4 pages, 2 figuresStatistical MechanicsFluid Dynamicstext